Articulation mechanism for surgical stapling device

ABSTRACT

A surgical device includes an elongate body, a tool assembly, a drive assembly, and an articulation mechanism for moving the tool assembly between a non-articulated position and articulated positions. The articulation mechanism includes an articulation link, a first pivot link that is positioned on a first side of a flexible beam, and a second pivot link positioned on a second side of the flexible beam. The first and second pivot links are configured to control the path of movement of the flexible beam of the drive assembly as the flexible beam is moved between its retracted and advanced positions in non-articulated and articulated positions of the tool assembly to maintain a predetermined distance of movement of the clamp member within the tool assembly constant.

FIELD

This technology is generally related to surgical devices for endoscopic use and, more specifically, to surgical devices including articulation mechanisms for articulating tool assemblies.

BACKGROUND

Various types of surgical devices used to endoscopically treat tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, and anastomoses procedures, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue.

One example of such a surgical device is a surgical stapling device. Surgical stapling devices include a tool assembly having an anvil assembly and a cartridge assembly, and a drive assembly that is movable through the tool assembly. Typically, the drive assembly includes a flexible drive beam and a clamp member that is supported on a distal end of the flexible drive beam. The drive assembly is movable to advance the clamp member through the tool assembly to approximate the cartridge and anvil assemblies and to advance an actuation sled through the cartridge assembly to eject staples from the cartridge assembly.

During laparoscopic or endoscopic surgical procedures, access to a surgical site is achieved through a small incision or through a narrow cannula inserted through a small entrance wounds in a patient. Because of limited area available to access the surgical site, many endoscopic devices include mechanisms for articulating the tool assembly of the device about a pivot axis in relation to a body portion of the device. When the tool assembly is in an articulated position and the drive beam is advanced to actuate the tool assembly, the drive beam bends about the pivot axis as the drive assembly is advanced to advance the clamp member through the tool assembly. This bending of the drive beam in relation to the pivot axis causes the drive beam to move to a position off the pivot axis and changes a stroke length of the drive beam required to fully actuate the tool assembly. This change in stroke length increases exponentially as the tool assembly is articulated over a greater angle and may adversely affect operation of the stapling device.

A continuing need exists in the art for an articulating mechanism for a surgical device that can maintain distance of advancement of a clamp member within a tool assembly constant in both non-articulated and articulated positions of the tool assembly.

SUMMARY

Aspects of this disclosure are directed to a surgical device having an elongate body, a tool assembly, a drive assembly, and an articulation mechanism for moving the tool assembly between a non-articulated position and articulated positions. The drive assembly includes a flexible beam and a clamp member that is supported on the flexible beam. The drive assembly is movable through a predetermined stroke to move the clamp member a predetermined distance through the tool assembly to actuate the tool assembly. The articulation mechanism includes an articulation link, a first pivot link that is positioned on a first side of the flexible beam and a second pivot link positioned on a second side of the flexible beam. The first pivot link has a convex guide surface that is engaged with the first side of the flexible beam and the second pivot link has a convex guide surface that is engaged with the second side of the flexible beam. The convex and concave guide surfaces are configured to control the path of movement of the flexible beam as the flexible beam is moved between its retracted and advanced positions in the non-articulated and articulated positions of the tool assembly to maintain the predetermined distance of movement of the clamp member within the tool assembly constant.

Aspects of this disclosure are directed to a surgical device that includes an elongate body, a tool assembly, a drive assembly, and an articulation mechanism. The elongate body defines a longitudinal axis and has a proximal portion a distal portion. The tool assembly is pivotably coupled to the distal portion of the elongate body and defines a longitudinal axis. The tool assembly is pivotable between a non-articulated position in which the longitudinal axis of the tool assembly is aligned with the longitudinal axis of the elongate body and articulated positions in which the longitudinal axis of the tool assembly is misaligned with the longitudinal axis of the elongate body. The drive assembly includes a flexible drive beam and a clamp member. The flexible drive beam has a proximal portion, a distal portion, a first side, and a second side. The distal portion supports the clamp member. The drive assembly is movable through a predetermined stroke length to move the clamp member within the tool assembly a predetermined distance. The articulation assembly includes an articulation link and first and second pivot links. The articulation link has a proximal portion and a distal portion. The first pivot link is positioned adjacent the first side of the flexible drive beam and has a proximal portion that is pivotably coupled to the distal portion of the articulation link and a distal portion that is pivotably coupled to the tool assembly. The second pivot link is positioned adjacent the second side of the flexible drive beam and has a distal portion that is coupled to the tool assembly. The first and second pivot links are configured to control a path of movement of the flexible beam as the flexible beam is moved between its retracted and advanced positions to maintain the predetermined distance of movement of the clamp member within the tool assembly constant in the non-articulated and articulated positions of the tool assembly.

In aspects of the disclosure, the first pivot link includes a convex guide surface that is engaged with the first side of the flexible drive beam to define a deformed portion in the flexible beam.

In some aspects of the disclosure, the second pivot link includes a concave guide surface that faces the second side of the flexible drive beam.

In certain aspects of the disclosure, the tool assembly is pivotably coupled to the distal portion of the elongate body about a pivot axis that is laterally offset from the longitudinal axis of the tool assembly.

In aspects of the disclosure, the second pivot link includes a proximal end that is in abutting relation to the distal portion of the elongate body.

In some aspects of the disclosure, the surgical device includes a retaining member that is secured to the elongate body adjacent the second pivot link to obstruct outward movement of the second pivot link.

In certain aspects of the disclosure, the tool assembly includes an anvil and a cartridge assembly that are pivotably coupled together such that the tool assembly is movable between open and clamped positions.

In aspects of the disclosure, the articulation link is positioned on the first side of the flexible drive beam.

In some aspects of the disclosure, the surgical device includes a stabilizing member that is positioned on each side of the flexible drive beam, and each of the stabilizing members extends from a position proximal of the pivot axis to a position distal of the pivot axis.

In certain aspects of the disclosure, each of the stabilizing members defines a centrally located concavity.

In aspects of the disclosure, each of the stabilizing members includes a proximal portion that is slidably engaged with the elongate body.

In some aspects of the disclosure, the surgical device includes a handle assembly that is coupled to the proximal portion of the elongate body.

In certain aspects of the disclosure, the tool assembly forms part of a reload assembly that includes a proximal body portion and the tool assembly.

In aspects of the disclosure, the proximal body portion has a proximal portion that is releasably coupled to the elongate body.

Other aspects of the disclosure are directed to a reload assembly that includes a proximal body portion, a tool assembly, a drive assembly, and an articulation mechanism. The proximal body portion defines a longitudinal axis and has a proximal portion and a distal portion. The tool assembly is pivotably coupled to the distal portion of the proximal body portion and defines a longitudinal axis. The tool assembly is pivotable between a non-articulated position in which the longitudinal axis of the tool assembly is aligned with the longitudinal axis of the proximal body portion and articulated positions in which the longitudinal axis of the tool assembly is misaligned with the longitudinal axis of the proximal body portion. The tool assembly includes an anvil and a cartridge assembly that are pivotable in relation to each other between open and clamped positions. The drive assembly includes a flexible drive beam and a clamp member. The flexible drive beam has a proximal portion, a distal portion, a first side, and a second side. The distal portion supports the clamp member. The drive assembly is movable through a predetermined stroke length to move the clamp member within the tool assembly a predetermined distance. The articulation assembly includes an articulation link and first and second pivot links. The articulation link has a proximal portion and a distal portion. The first pivot link is positioned adjacent the first side of the flexible drive beam and has a proximal portion that is pivotably coupled to the distal portion of the articulation link and a distal portion that is pivotably coupled to the tool assembly. The second pivot link is positioned adjacent the second side of the flexible drive beam and has a distal portion that is coupled to the tool assembly. The first and second pivot links are configured to control a path of movement of the flexible beam as the flexible beam is moved between its retracted and advanced positions to maintain the predetermined distance of movement of the clamp member within the tool assembly constant in the non-articulated and articulated positions of the tool assembly.

Other features of the disclosure will be appreciated from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the disclosure are described herein below with reference to the drawings, wherein:

FIG. 1 is a side perspective view of a powered version of a surgical device including an articulation mechanism according to aspects of the disclosure with a tool assembly of the stapling device in a non-articulated position;

FIG. 2 is a side perspective view of a manual version of a surgical device including the articulation mechanism according to aspects of the disclosure with the tool assembly of the stapling device in an articulated position;

FIG. 3 is an exploded, side perspective view of a proximal body portion, a mounting assembly, and pivot links of a reload assembly of the surgical device shown in FIGS. 1 and 2;

FIG. 3A is a side perspective view of pivot plates and retaining member of the reload assembly shown in FIG. 3;

FIG. 4 is an exploded, side perspective view of the mounting assembly and pivot links of the reload assembly shown in FIG. 3;

FIG. 5 is a side perspective view of the assembled mounting assembly and pivot links shown in FIG. 4;

FIG. 6 is a side perspective view of the distal portion of the reload assembly shown in FIG. 3 with an outer tube of the proximal body portion shown in phantom and the tool assembly in a non-articulated position;

FIG. 7 is a side perspective view of the distal portion of the reload assembly shown in FIG. 6 with the anvil assembly removed and a half section of the housing of the proximal body portion and the outer tube removed with the tool assembly in a non-articulated position;

FIG. 8 is a top view of the distal portion of the reload assembly shown in FIG. 6 with a drive assembly of the reload assembly shown in phantom and the tool assembly in a non-articulated position;

FIG. 9 is an enlarged view of the indicated area of detail shown in FIG. 8;

FIG. 10 is a cross-sectional view taken along section line 10-10 of FIG. 8;

FIG. 11 is a cross-sectional view taken along section line 11-11 of FIG. 8;

FIG. 12 is a cross-sectional view taken along section line 12-12 of FIG. 9;

FIG. 13 is a top view of a central portion of the reload assembly shown in FIG. 8 with the tool assembly in the articulated position;

FIG. 14 is a cross-sectional view taken along section line 14-14 of FIG. 13 with the tool assembly in a first articulated position; and

FIG. 15 is a cross-sectional view through the central portion of the reload assembly shown in FIG. 13 with the tool assembly in a second articulated position.

DETAILED DESCRIPTION

The disclosed surgical device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. However, it is to be understood that aspects of the disclosure are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosure in virtually any appropriately detailed structure.

In this description, the term “proximal” is used generally to refer to that portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term “endoscopic” is used generally to refer to endoscopic, laparoscopic, arthroscopic, and/or any other procedure conducted through a small diameter incision or cannula, and the term “clinician” is used generally to refer to medical personnel including doctors, nurses, and support personnel. Further, directional terms such as “front”, “rear”, “upper”, “lower”, “top”, “bottom”, and similar terms are used to assist in understanding the description and are not intended to limit the disclosure.

The disclosed surgical device includes a body portion and a tool assembly that is coupled to the body portion by a pivot member to facilitate articulation of the tool assembly in relation to the body portion. The body portion includes an articulation mechanism and a drive assembly. The drive assembly has a resilient drive beam and a clamp member that is positioned within the tool assembly. The drive assembly is movable between retracted and advanced positions over a predetermined stroke to advance the clamp member within the tool assembly a predetermined distance to move the tool assembly from an open position to a clamped position and to eject staples from the tool assembly. The articulation mechanism includes pivot links that engage the drive assembly as the drive assembly moves through the predetermined stroke to control the path of movement of the drive assembly and maintain the predetermined distance of movement of the clamp member within the tool assembly constant in the non-articulated and articulated positions of the tool assembly.

FIG. 1 illustrates a surgical device according to aspects of the disclosure shown generally as surgical device 10. The surgical device 10 includes a handle assembly 12, an elongate body 14, and a tool assembly 16. The elongate body 14 defines a central longitudinal axis “X” (FIG. 1) and the tool assembly 16 defines a longitudinal axis “Y” (FIG. 13). The tool assembly 16 is pivotally coupled to the elongate body 14 and can pivot between a non-articulated position (FIG. 1) in which the longitudinal axes “X” and “Y” of the elongate body 14 and tool assembly 16 are aligned with each other to articulated positions in which the longitudinal axes “X” and “Y” of the elongate body 14 and tool assembly 16 are misaligned with each other (FIG. 13).

The handle assembly 12 includes a body 12 a that defines a stationary handle 18 and includes actuation buttons 20 that are operable to initiate operation of the surgical device 10, i.e., approximation of the tool assembly 16, articulation of the tool assembly 16, and firing of staples from the tool assembly 16. In aspects of the disclosure, the handle assembly 12 supports a rotation knob 22 that is coupled to a proximal portion 14 a of the elongate body 14 and is rotatable to rotate the elongate body 14 and the tool assembly 16 in relation to the handle assembly 12 about the longitudinal axis “X”. While the surgical device 10 may be configured to fire staples, it is contemplated that the surgical device 10 may be adapted to fire any other suitable fasteners such as clips and two-part fasteners. Although the surgical device 10 is illustrated as a surgical stapling device 10, it is also envisioned that certain components described herein may be adapted for use in other types of articulating endoscopic surgical instruments including endoscopic forceps, graspers, dissectors, other types of surgical stapling instruments, powered vessel sealing devices and/or cutting devices.

Although FIG. 1 illustrates the stapling device 10 as including a powered handle assembly 12, it is envisioned that the stapling device 10′ can include a handle assembly 12′ that is manually actuated such as illustrated in FIG. 2. The manually actuated handle assembly 12′ supports the elongate body 14 and the tool assembly 16 and includes a body 12 a′ that defines a stationary handle 18′. The handle assembly 12′ includes a pivotable trigger 20′ that is movable in relation to the stationary handle 18′ to actuate the tool assembly 16. The stationary handle 12′ supports a rotation knob 22′ that is engaged with the elongate body 14 such that rotation of the rotation knob 22′ causes rotation of the elongate body 14 and the tool assembly 16 in relation to the handle assembly 12′. The stapling device 10′ also supports an articulation lever 24′ that is rotatable to articulate the tool assembly 16.

In aspects of the disclosure, the tool assembly 16 forms part of a reload assembly 40 that is releasably coupled to the elongate body 14 and includes a proximal body portion 42, the tool assembly 16, and a mounting assembly 44 that pivotably couples the tool assembly 16 to the distal portion of the proximal body portion 42. The proximal body portion 42 is coaxial with the longitudinal axis “X” of the elongate body 14 and has a proximal portion 42 a that is releasably coupled to a distal portion 14 a of the elongate body 14. It is envisioned that the tool assembly 16 can be pivotably secured to the elongate body 14 via the mounting assembly 44 and need not form part of a reload assembly.

FIGS. 1-3 illustrate the tool assembly 16 which includes an anvil 50 and a cartridge assembly 52. The anvil 50 is coupled to the cartridge assembly 52 by pivot members 54 (FIG. 3) that facilitate movement of the anvil 50 in relation to the cartridge assembly 52 between open and clamped positions. The cartridge assembly 52 includes a channel member 56 and a staple cartridge 58. The channel member 56 defines a cavity 56 a that receives the staple cartridge 58. In aspects of the disclosure, the staple cartridge 58 is releasably received within the channel member 56 and can be replaced to facilitate reuse of the stapling device 10 (FIGS. 1 and 2). Alternately, it is envisioned that the staple cartridge 58 can be fixedly retained within the channel member 56 and the entire reload assembly can be replaced to facilitate reuse of the stapling device 10. Although the cartridge assembly 52 is shown to pivot towards the anvil 50, it is envisioned that the cartridge assembly 52 could be stationary and the anvil 50 could pivot towards the cartridge assembly 52.

FIG. 3 illustrates an exploded view of the reload assembly 40 which includes the proximal body portion 42, the mounting assembly 44 (FIG. 1), and the tool assembly 16. The mounting assembly 44 includes a first mounting member 60 and a second mounting member 62 that are secured together with screws or rivets 64 to define an enclosed channel 66 between the first and second mounting members 60 and 62, respectively. The second mounting member 62 defines threaded bores 68. The channel member 56 of the cartridge assembly 52 includes a proximal portion that defines bores 70 that receive the pivot members 54. The pivot members 54 extend through the bores 70 in the proximal portion of the channel member 56 and into the threaded bores 68 of the second mounting member 62 to pivotably secure the cartridge assembly 52 to the mounting assembly 44. The pivot members 54 also extend through openings 72 in a proximal portion of the anvil 50 to secure the anvil 50 to the mounting assembly 44. The proximal portion of the anvil 50 defines cutouts 74 through which the rivets 64 pass to fixedly secure the anvil 50 to the mounting assembly 44.

The proximal body portion 42 of the reload assembly 40 includes a housing 80 (FIG. 6), a drive assembly 82, and an articulation mechanism 84 (FIG. 7). The housing 80 is formed from first and second half-sections 80 a and 80 b that are secured together to define internal channels that facilitate longitudinal movement of the drive assembly 82 and the articulation mechanism 84 within the housing 80. Each of the housing half-sections 80 a and 80 b includes a distal portion that defines a stepped cutout 86 (only one is shown). The first half-section 80 a includes a proximal portion 88 that is adapted to be releasably coupled to the distal portion of the elongate body 14 (FIG. 2). U.S. Pat. No. 8,132,706 (hereinafter “the '706 Patent”) discloses a reload assembly having a proximal body portion including a housing that is adapted to releasably engage a body portion of a surgical stapling device suitable for use with the disclosed surgical device.

FIGS. 3-5 illustrate the mounting assembly 44 which as described above includes mounting members 60 and 62 that are secured together with rivets 64. Each of the mounting members 60 and 62 includes a proximal portion that includes or defines a pivot member 90 (only one is shown). The pivot members 90 are coaxial and define an articulation axis “Z” (FIG. 2) about which the tool assembly 16 articulates. The articulation axis “Z” is spaced laterally of the central longitudinal axis “X” of the elongate body portion 14 (FIG. 2) and the proximal body portion 42 of the reload assembly 40. The mounting assembly 44 also includes first and second pivot plates 92 a and 92 b. Each of the pivot plates 92 a and 92 b includes a body having a stepped configuration that corresponds to the configuration of one of the stepped cutouts 86 formed in the housing half-sections 80 a and 80 b. Each of the pivot plates 92 a and 92 b also includes a distal portion that defines a bore 94 that receives one of the pivot members 90 of the mounting members 60 and 62. The bodies of the pivot plates 92 a and 92 b are received in the respective stepped cutouts 86 of the housing half-sections 80 a and 80 b and the pivot members 90 of the first and second mounting members 60 and 62 are received within the respective bores 94 of the pivot plates 92 a and 92 b to pivotably secure the mounting assembly 44 and tool assembly 16 to the proximal body portion 42 of the reload assembly 40 about the articulation axis “Z”.

The articulation mechanism 84 (FIG. 7) of the reload assembly 40 includes an articulation link 100 and first and second pivot links 102 and 104. The articulation link 100 has a proximal portion and a distal portion. The proximal portion is adapted to engage an articulation drive member (not shown) within the elongate body 14 (FIG. 2) when the reload assembly 40 (FIG. 2) is coupled to the elongate body 14. In aspects of the disclosure, the proximal portion of the articulation link 100 includes a transverse portion 106 that is adapted to engage the articulation drive member (not shown) within the elongate body 14. The distal portion of the articulation link 100 defines a through bore 108 that is pivotably coupled to the first pivot link 102 as described in further detail below. The articulation link 100 is supported within a channel defined within the housing 80 (FIG. 6) of the proximal body portion 42 for longitudinal movement between retracted and advanced positions.

FIGS. 4 and 5 illustrate the first pivot link 102 which includes a body 110 (FIG. 4) having a curved configuration and proximal and distal pivot members 112 and 114. The proximal pivot member 112 is received within the through bore 108 in the distal portion of the articulation link 100 to pivotably couple the first pivot link 102 to the distal portion of the articulation link 100. The distal pivot member 114 of the first pivot link 102 is pivotably received between the first and second mounting members 60 and 62 to pivotably couple the first pivot link 102 to the mounting assembly 44 (FIG. 6). The body 110 of the first pivot link 102 includes a convex guide surface 116 that faces the second pivot link 104 and extends inwardly across the longitudinal axis “X” (FIG. 12) of the elongate body 14 and proximal body portion 42.

The second pivot link 104 includes a body 120 that includes a distal pivot member 122 and a proximal abutment member 124. The distal pivot member 122 of the second pivot link 104 is received between the first and second mounting members 60 and 62 to pivotably couple the second pivot link 104 to the mounting assembly 44 (FIG. 6). The abutment member 124 is engaged with a wall 126 on the distal portion of the housing half-section 80 b (FIG. 3). The pivot link 104 includes a concave guide surface 132 that faces the convex guide surface 116 of the first pivot link 102.

A retaining member 130 (FIG. 3A) has a C-shaped body and is secured to the pivot plates 92 a and 92 b outwardly of the pivot link 104 to limit outward pivotable movement of the pivot link 104 (FIG. 3A). In aspects of the disclosure, ends of the C-shaped body of the retaining member 130 are welded to the pivot plates 92 a and 92 b to secure the retaining member 130 outwardly of the pivot link 104.

FIG. 3 illustrates the drive assembly 82 which includes a flexible drive beam 140 and a clamp member 42. The flexible drive beam 140 has a proximal portion and a distal portion. The proximal portion of the drive beam 140 is coupled to a control rod (not shown) within the elongate body 14 (FIG. 2) and is movable in response to movement of the control rod between retracted and advanced positions. In aspects of the disclosure, the flexible drive beam 140 is formed from stacked sheets of material and can bend about the articulation axis “Z” (FIG. 2) when the tool assembly 16 is in an articulated position and the surgical device 10 is fired. The clamp member 142 of the drive assembly 82 is secured to the distal portion of the drive beam 140 and is movable through the tool assembly 16 when the flexible drive beam 140 is moved between its retracted and advanced positions to actuate the tool assembly 16. In aspects of the disclosure, the clamp member 142 of the drive assembly 82 has an I-beam configuration and supports a knife blade 142 a. For a detailed description of the construction and operation of the drive assembly 82, see the '706 Patent.

The reload assembly 40 includes a flexible stabilizing member 150 and 152 positioned on each side of the flexible drive beam 140. Each of the flexible stabilizing members 150 and 152 extends from the proximal body portion 42 through the channel 66 defined by the mounting assembly 44 and has a distal end fixedly coupled to the tool assembly 16 and a proximal end received within the housing 44 of the reload assembly 40 for sliding movement. The stabilizing member 150 defines a centrally located concavity 150 a that receives the convex guide surface 116 of the first pivot member 102 and the stabilizing member 152 defines a centrally located convexity 152 a that is received within the concave guide surface 132 of the pivot link 104.

In some aspects of the disclosure, the disclosed tool assembly 16 of the reload assembly 40 articulates in a single direction over a range of articulation of about 90 degrees in a direction towards the pivot link 102. FIGS. 6-12 illustrate the reload assembly 40 with the tool assembly 16 in a non-articulated position. In the non-articulated position, the flexible drive beam 140 of the drive assembly 82 is spaced laterally of the articulation axis “Z” (FIG. 2) and the longitudinal axis “X” along its length in a direction towards the second pivot link 104 and is engaged by the stabilizing member 150 in the area adjacent the convex guide surface 116 of the first pivot link 102. The configuration of the convex guide surface 116 of the first pivot link 102 deforms the flexible drive beam 140 a to define a deformed portion 140 a of the flexible drive beam 140 which is spaced further outwardly of the longitudinal axis “X” of the proximal body portion 42 and of the articulation axis “Z” than the proximal and distal portions of the flexible drive beam 140. The deformed portion 140 a shortens the effective longitudinal length of the drive beam 140 to provide the appropriate stroke length to advance the clamp member 142 a predetermined distance within the tool assembly 16 to properly actuate the tool assembly 16.

FIGS. 13 and 14 illustrate the reload assembly 40 of the surgical device 10 (FIG. 2) with the tool assembly 16 in a first articulated position (approximately 30 degrees). In order to articulate the tool assembly 16 of the reload assembly 40, the articulation link 100 is retracted in the direction of arrow “A” to retract the first pivot link 102 and pivot the tool assembly 16 in the direction of arrow “B” in FIG. 14 about the articulation axis “Z” (FIG. 2) defined by the pivot members 90 to the side of the flexible drive beam 140 that supports the first pivot link 102. As illustrated, the deformed portion 140 a of the flexible drive beam 140 becomes less pronounced as the tool assembly 16 is articulated to adjust the effective longitudinal length of the flexible drive beam 140 to move the clamp member 142 a a predetermined distance within the tool assembly 16 to properly actuate the tool assembly 16. As illustrated, as the tool assembly 16 is articulated, the flexible drive beam 140 moves inwardly to a position closer to the pivot axis “Z” (FIG. 2) defined by the pivot members 90.

FIG. 15 illustrates the reload assembly 40 of the surgical device 10 (FIG. 2) with the tool assembly 16 in a second articulated position (approximately 90 degrees). As illustrated, as the tool assembly 16 is articulated about the pivot axis “Z” (FIG. 2) defined by the pivot members 90, the deformed portion 140 a of the flexible drive beam 140 is diminished such that the effective longitudinal length of the flexible drive beam 140 is maximized to move the clamp member 142 a the predetermined distance within the tool assembly 16 to properly actuate the tool assembly 16.

As summarized above, the configuration of the convex and concave guide surfaces 116 and 132 of the first and second pivot links 102 and 104, respectively, controls the path of movement of the flexible drive beam 140 in relation to the pivot axis “Z” to ensure that the clamp member 142 moves the predetermined distance within the tool assembly 16 to properly actuate the tool assembly 16.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary aspects of the disclosure. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described aspects of the disclosure. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

What is claimed is:
 1. A surgical device comprising: an elongate body defining a longitudinal axis, the elongate body having a proximal portion and a distal portion; a tool assembly pivotably coupled to the distal portion of the elongate body, the tool assembly defining a longitudinal axis and pivotable between a non-articulated position in which the longitudinal axis of the tool assembly is aligned with the longitudinal axis of the elongate body and articulated positions in which the longitudinal axis of the tool assembly is misaligned with the longitudinal axis of the elongate body; a drive assembly including a flexible drive beam and a clamp member, the flexible drive beam having a proximal portion, a distal portion, a first side, and a second side, the distal portion supporting the clamp member, the drive assembly being movable through a predetermined stroke length to move the clamp member within the tool assembly a predetermined distance; and an articulation assembly including an articulation link and first and second pivot links, the articulation link having a proximal portion and a distal portion, the first pivot link positioned adjacent the first side of the flexible drive beam and having a proximal portion pivotably coupled to the distal portion of the articulation link and a distal portion pivotably coupled to the tool assembly, the second pivot link positioned adjacent the second side of the flexible drive beam and having a distal portion coupled to the tool assembly, the first and second pivot links being engaged with the flexible beam to control a path of movement of the flexible beam as the flexible beam is moved between its retracted and advanced positions to maintain the predetermined distance of movement of the clamp member within the tool assembly constant in the non-articulated and articulated positions of the tool assembly.
 2. The surgical device of claim 1, wherein the first pivot link includes a convex guide surface that is engaged with the first side of the flexible drive beam when the tool assembly is in the non-articulated position to define a deformed portion in the flexible drive beam.
 3. The surgical device of claim 2, wherein the second pivot link includes a concave guide surface that faces the second side of the flexible drive beam.
 4. The surgical device of claim 1, wherein the tool assembly is pivotably coupled to the distal portion of the elongate body about a pivot axis, the pivot axis being laterally offset from the longitudinal axis of the tool assembly.
 5. The surgical device of claim 1, wherein the second pivot link includes a proximal end that is in abutting relation to the distal portion of the elongate body.
 6. The surgical device of claim 5, further including a retaining member secured to the elongate body adjacent the second pivot link to obstruct outward movement of the second pivot link.
 7. The surgical device of claim 1, wherein the tool assembly includes an anvil and a cartridge assembly, the anvil and the cartridge assembly being pivotably coupled together such that the tool assembly is movable between open and clamped positions.
 8. The surgical device of claim 1, wherein the articulation link is positioned on the first side of the flexible drive beam.
 9. The surgical device of claim 1, further including a stabilizing member positioned on each side of the flexible drive beam, each of the stabilizing members extending from a position proximal of the pivot axis to a position distal of the pivot axis.
 10. The surgical device of claim 9, wherein each of the stabilizing members defines a centrally located concavity.
 11. The surgical device of claim 10, wherein each of the stabilizing members includes a proximal portion that is slidably engaged with the elongate body.
 12. The surgical device of claim 1, further including a handle assembly, the handle assembly coupled to the proximal portion of the elongate body.
 13. The surgical device of claim 1, wherein the tool assembly forms part of a reload assembly, the reload assembly including a proximal body portion and the tool assembly, the proximal body portion having a proximal portion releasably coupled to the elongate body.
 14. A reload assembly comprising; a proximal body portion defining a longitudinal axis and having a proximal portion and a distal portion; a tool assembly pivotably coupled to the distal portion of the proximal body portion, the tool assembly defining a longitudinal axis and being pivotable between a non-articulated position in which the longitudinal axis of the tool assembly is aligned with the longitudinal axis of the proximal body portion and articulated positions in which the longitudinal axis of the tool assembly is misaligned with the longitudinal axis of the proximal body portion, the tool assembly including an anvil and a cartridge assembly, the anvil and cartridge assembly pivotable in relation to each other between open and clamped positions; a drive assembly including a flexible drive beam and a clamp member, the flexible drive beam having a proximal portion, a distal portion, a first side, and a second side, the distal portion supporting the clamp member, the drive assembly being movable through a predetermined stroke length to move the clamp member within the tool assembly a predetermined distance; and an articulation assembly including an articulation link and first and second pivot links, the articulation link having a proximal portion and a distal portion, the first pivot link positioned adjacent the first side of the flexible drive beam and having a proximal portion pivotably coupled to the distal portion of the articulation link and a distal portion pivotably coupled to the tool assembly, the second pivot link positioned adjacent the second side of the flexible drive beam and having a distal portion coupled to the tool assembly, the first and second pivot links being engaged with the flexible beam to control a path of movement of the flexible beam as the flexible beam is moved between its retracted and advanced positions to maintain the predetermined distance of movement of the clamp member within the tool assembly constant in the non-articulated and articulated positions of the tool assembly.
 15. The reload assembly of claim 14, wherein the first pivot link includes a convex guide surface that is engaged with the first side of the flexible drive beam when the tool assembly is in the non-articulated position to define a deformed portion in the flexible drive beam.
 16. The reload assembly of claim 15, wherein the second pivot link includes a concave guide surface that faces the second side of the flexible drive beam.
 17. The reload assembly of claim 14, wherein the tool assembly is pivotably coupled to the distal portion of the elongate body about a pivot axis, the pivot axis being laterally offset from the longitudinal axis of the tool assembly.
 18. The reload assembly of claim 14, wherein the second pivot link includes a proximal end that is in abutting relation to the distal portion of the elongate body.
 19. The reload assembly of claim 18, further including a retaining member secured to the elongate body adjacent the second pivot link to obstruct outward movement of the second pivot link.
 20. The reload assembly of claim 14, further including a stabilizing member positioned on each side of the flexible drive beam, each of the stabilizing members extending from a position proximal of the pivot axis to a position distal of the pivot axis and defining a centrally located concavity. 